Soy can cause the same reaction as casein...My son laughs at night from bananas. He has been on melatonin since the age of 2 when he saw Dr. Lonsdale in Cleveland. He is now almost 10. There is a break in his chemistry that makes it VERY difficult to sleep and melatonin is the end product of a chain reaction that does not occur properly with my boy. Good Luckgloria